This invention relates generally to drill bits and/or other downhole tools. More particularly, this invention relates to drill bits and/or other downhole tools that include one or more high angle nozzle sockets machined therein and the methods for forming such high angle nozzle sockets.
FIG. 1 shows a perspective view of a drill bit 100 in accordance with the prior art. FIG. 2 shows a bottom plan view of the drill bit 100 in accordance with the prior art. Referring to FIGS. 1 and 2, the drill bit 100 includes a bit body 110 that is coupled to a shank 115 and is designed to rotate in a counter-clockwise direction 190. The drill bit 100 is fabricated using machined steel or any other suitable material that can be machined, such as from a bar stock. The shank 115 includes a threaded connection 116 at one end 120. The threaded connection 116 couples to a drill string (not shown) or some other equipment that is coupled to the drill string. The threaded connection 116 is shown to be positioned on the exterior surface of the one end 120. This positioning assumes that the drill bit 100 is coupled to a corresponding threaded connection located on the interior surface of a drill string (not shown). However, the threaded connection 116 at the one end 120 is alternatively positioned on the interior surface of the one end 120 if the corresponding threaded connection of the drill string (not shown) is positioned on its exterior surface in other exemplary embodiments. A bore 205 is formed longitudinally through the shank 115 and a plenum 210 is formed within the bit body 110. The bore 205 communicates drilling fluid from within the drill string to the plenum 210, which then communicates the drilling fluid to a drill bit face 111, on the exterior surface of the drill bit 100, via one or more nozzles 114 during drilling operations. A flowpath 215 is formed within the bit body 110 and extends from the plenum 210 to the nozzle 114. Typically, the flowpaths 215 are formed via machining and are substantially linear within the drill bit 100.
The bit body 110 includes a plurality of gauge sections 150 and a plurality of blades 130 extending from the drill bit face 111 of the bit body 110 towards the threaded connection 116, where each blade 130 extends to and terminates at a respective gauge section 150. The blade 130 and the respective gauge section 150 are formed as a single component, but are formed separately in certain drill bits 100. The drill bit face 111 is positioned at one end of the bit body 110 furthest away from the shank 115. The plurality of blades 130 form the cutting surface of the drill bit 100. One or more of these plurality of blades 130 are either coupled to the bit body 110 or are integrally formed with the bit body 110. The gauge sections 150 are positioned at an end of the bit body 110 adjacent the shank 115. The gauge section 150 includes one or more gauge cutters (not shown) in certain drill bits 100. The gauge sections 150 typically define and hold the full hole diameter of the drilled hole.
Each of the blades 130 and gauge sections 150 include a leading edge section 132, a face section 134, a trailing edge section 136, and an inner section 138. The face section 134 extends from one longitudinal end of the trailing edge section 136 to a longitudinal end of the leading edge section 132. The leading edge section 132 faces in the direction of rotation 190, while the trailing edge section 136 faces oppositely from the direction of rotation 190. The inner section 138 extends from one latitudinal end of the trailing edge section 136 to a latitudinal end of the leading edge section 132 and from the drill bit face 111 to an end of the face section 134. A junk slot 122 is formed between each consecutive blade 130, which allows for cuttings and drilling fluid to return to the surface of the wellbore (not shown) once the drilling fluid is discharged from the nozzles 114. A plurality of cutters 140 are coupled to each of the blades 130 and extend outwardly from the surface of the blades 130 to cut through earth formations when the drill bit 100 is rotated during drilling. One type of cutter 140 used within the drill bit 100 is a PDC cutter; however other types of cutters are contemplated as being used within the drill bit 100. The cutters 140 and portions of the bit body 110 deform the earth formation by scraping and/or shearing depending upon the type of drill bit 100. Although one embodiment of the drill bit has been described, other configurations of drill bit embodiments or other downhole tools, which are known to people having ordinary skill in the art, are applicable to exemplary embodiments of the present invention.
During drilling of a borehole, the drill bit 100 rotates to cut through an earth formation to form a wellbore therein. This cutting is typically performed through scraping and/or shearing action according to certain drill bits 100, but is performed through other means based upon the type of drill bit used. Drilling fluid (not shown) exits the drill bit 100 through one or more nozzles 114 and facilitates the removal of the cuttings from the borehole wall back towards the surface. As the drill bit 100 rotates and the drilling fluid with cuttings are at the bottom of the borehole, some cuttings adhere to the drill bit 100 causing inefficiencies. Thus, the nozzles 114 can facilitate removal of portions of these cuttings that are adhered to the drill bit 100.
High angle nozzles, or high angle nozzle sockets, also known as lateral jets, are known in the drill bit casting art. Multiple component casting displacements have been used historically to cast the angled or curved passage required to mate the inlet end of the fluid path adjacent the drill bit inner plenum to the nozzle socket outlet end adjacent to the bit face. In the drill bit casting art, these non-linear displacements have been used in cast tungsten carbide matrix bit manufacture and in the manufacture of stellite cast body bits. Stellite alloy is a range of cobalt-chromium alloys designed for wear resistance and may also contain tungsten or molybdenum and a small but important amount of carbon.
High angle nozzles sockets are desirable in drill bits for some applications, for example, drilling shale, where bit cleaning highly affects the performance factor of the bit. However, these high angle nozzle sockets have not been previously employed in bit bodies machined from bar stock due to the lack of a method to install the hole geometry, angled or curved, in a machining process.
The drawings illustrate only exemplary embodiments of the invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments.